A security guard on his last day on the job at a Brooklyn shipyard was crushed to death while inspecting a truck as the driver – unaware of the unfolding tragedy – drove off and dragged the victim’s body for 10 blocks, police said yesterday.

David Frauenberg, 37, was examining a tractor-trailer at the Old Dominion Shipyard at 500 Gardner St. in Greenpoint around 5:20 a.m. Thursday when the horrific accident occurred, law-enforcement sources said.

Frauenberg, a security guard for Gold Shield Security and Investigation, was standing between two of the truck’s trailers when the driver, who was not immediately identified, began to drive away.

The driver didn’t even know Frauenberg was trapped under the vehicle until after he had driven about 10 blocks and reached the corner of Meeker Avenue and Russell Street.

That’s when he checked the rear-view mirror and spotted the Ainslie Street resident stuck beneath the truck’s front tires.

The driver was not charged.

Frauenberg’s family said David was a hardworking man who worked two jobs – the other at a senior center – to take care of his 2-year-old son, D.J.

“He would come home so tired, but he always took care of his son, said Frauenberg’s sister, Dawn Cruz, 36. “This was supposed to be his last day.”

Cruz said she is heartbroken over her brother’s death.

“He busted his hump and look what happened,” she said. “We love him and we miss him.”